Added optional argument for GeometryColumn to use WKT internally,
although only postgis can handle it currently
Corrected issue with isinstance checks for PersistentSpatialElement objects.
Now 'coords' and 'geom_type' properties no longer require additional queries.
Added 'geom_wkt' property to PersistentSpatialElement.
Performs equivalent functionality of 'geom_wkb', returning value loaded from the database.
Changed Lake mapper to use WKT internally in postgis tests
Postgis tests now check Lake geom_wkt
Added 'geom_type' test for postgis
Documented equals and not equals spatial comparisons in general usage and
NULL/None usage
GeometryWKTExtensionColumn will raise exception if non postgres/postgis
dialect
Added explanation of 'wkt_internal' usage to documentation.
Trying to use WKT internal on none PostGIS dialect now raises SAWarning,
defaulting back to WKB internally, rather than throwing an exception.
Changed wkt_internal to be option of Geometry type
Updated postgis test so wkt_internal is part of Lake Geometry type
Minor doc change to reflect wkt_internal is now part of Geometry type
add aggregate prefix
add postgis tests for aggregate functions
remove untested parts
Merge pull request #8 from kwirk/null_comparison

Documented equals and not equals spatial comparisons.
remove aggregate prefix, add support comment
add example of aggregation
Merge pull request #9 from kwirk/postgis_wkt

adds 'wkt_internal' property for 'Geometry' to use WKT internally (only for PostGIS currently)
add .gitignore